SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c801099a6e6028d641757df3a925d2cf2fc560feea20701f80774844d9f0aaa' 
  AND token = 'h6KslRwXq6Q7J+T/r2ddC/bzDSMs93HbMWdPSLqsRLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}